title: Mapping acute systemic effects of inhaled particulate matter and ozone: multiorgan gene expression and glucocorticoid activity.
abstract: Recent epidemiological studies have demonstrated associations between air pollution and adverse effects that extend beyond respiratory and cardiovascular disease, including low birth weight, appendicitis, stroke, and neurological/neurobehavioural outcomes (e.g., neurodegenerative disease, cognitive decline, depression, and suicide). To gain insight into mechanisms underlying such effects, we mapped gene profiles in the lungs, heart, liver, kidney, spleen, cerebral hemisphere, and pituitary of male Fischer-344 rats immediately and 24h after a 4-h exposure by inhalation to particulate matter (0, 5, and 50mg/m(3) EHC-93 urban particles) and ozone (0, 0.4, and 0.8 ppm). Pollutant exposure provoked differential expression of genes involved in a number of pathways, including antioxidant response, xenobiotic metabolism, inflammatory signalling, and endothelial dysfunction. The mRNA profiles, while exhibiting some interorgan and pollutant-specific differences, were remarkably similar across organs for a set of genes, including increased expression of redox/glucocorticoid-sensitive genes and decreased expression of inflammatory genes, suggesting a possible hormonal effect. Pollutant exposure increased plasma levels of adrenocorticotropic hormone and the glucocorticoid corticosterone, confirming activation of the hypothalamic-pituitary-adrenal axis, and there was a corresponding increase in markers of glucocorticoid activity. Although effects were transient and presumably represent an adaptive response to acute exposure in these healthy animals, chronic activation and inappropriate regulation of the hypothalamic-pituitary-adrenal axis are associated with adverse neurobehavioral, metabolic, immune, developmental, and cardiovascular effects. The experimental data are consistent with epidemiological associations of air pollutants with extrapulmonary health outcomes and suggest a mechanism through which such health effects may be induced.
authors.affiliation: Hazard Identification Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada. errol.thomson@hc-sc.gc.ca
authors.forename: Errol M
authors.initials: EM
authors.lastname: Thomson
authors.forename: Djordje
authors.initials: D
authors.lastname: Vladisavljevic
authors.forename: Susantha
authors.initials: S
authors.lastname: Mohottalage
authors.forename: Prem
authors.initials: P
authors.lastname: Kumarathasan
authors.forename: Renaud
authors.initials: R
authors.lastname: Vincent
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D003345:Corticosterone / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010126:Ozone / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity*; D010913:Pituitary-Adrenal System / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction / Q000187:drug effects; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D000393:Air Pollutants; D005938:Glucocorticoids; D052638:Particulate Matter; D010126:Ozone; D003345:Corticosterone
keywords: air pollution; glucocorticoid; hypothalamic-pituitary-adrenal axis; ozone; particulate matter; real-time PCR.; systemic effects